Tube bending machine with pivoted sweep arm



Jan. 28, 1947. R. FQBU-RKE I v TUBE BENDING- MACHINE WITH PIVOTED SWEEPARM Filed June 28, 1943 2 Sheets-Sheet 1 MN 9w QN mu Jan. 28, 1947.BURKE 2,414,926

TUBE BENDING- MACHINE WITH PIVOTED SWEEP ARM Patented Jan. 28, 1947 TUBEBENDING MACHINE WITH PIVOTED SWEEP ARM Robert F. Burke, Phoenixville, Paassignor to Boiler Engineering & Supply 00., Phoenixville,

Pa., a partnership com and Robert F. Burke posed of Russell E. KeenApplication June 28, 1943, Serial No. 492,631

Claims.

My invention relates to a new and useful tube bending machine and hasfor one of its objects to provide an exceedingly simple and effectiveapparatus that may be operated manually with considerable speed byrelatively cheap labor thus greatly reducing the cost of bending tubessuch as are used in steam power or other boilers.

Another object of the invention is to so dispose the elements of thapparatus relative to one another that either one, two or three bendsmay be made in a tube when the latter is once clamped in the machinethus positively insuring that all bends will be in pro-per alignment.While the most common number of bends in boiler tubes is two there aresome instances where three are required and a few cases where one bendis sufficient. In any case, after clamping a tube at one point, inproper location, the necessary bends can be made without moving orrelocating the tube.

Another object of this invention is to provide a construction thatallows the positions of the bending dies to be preselected forpredetermining the points at which a number of similar tubes will bebent.

A further object of this invention is to provide a unique means, whichis adjustable, for initially positioning the tubes in the machine.

With the above and other objects in view this invention consists of thedetails of construction and combination of elements hereinafter setforth and then designated by the claims.

In order that those skilled in the art to which this inventionappertains may understand how to make and use the same I will describeits construction in detail referring by numerals to the accompanyingdrawings forming a part hereof, in which:

Fig. 1 is a plan view of the tube bending machine or apparatus.

Fig. 2 is a front elevation thereof.

Fig. 3 is an enlarged fragmentary plan view of the machine in the regionof one of the bending dies.

Fig. 4 is a cross sectional view of Fig. 3.

Fig. 5 is a section on the line 55 of Fig. 3, showing the clamp in anopen position.

Fig. 6 is an edge View of tube bending lever and component parts.

Fig. '7 is a view similar to Fig. 5 showing the clamp in a closedposition.

Fig. 8 is a section on the line 88 of Fig. '7 showing the relativeposition of the jaw in dotted lines.

Fig. 9 is a section on the line 9-9 of Fig. '7.

Figs. 10, 11 and 12 are isometric views of several stop pins.

Fig. 13 is an end view of the means for locating the tube bends.

In carrying out my invention as herein embodied 15 represents a suitablesupporting frame, the top cross bars of which constitute a bench l6. fortemporarily holding tubes that have been bent. On said supporting frameI5, preferably as a part thereof, is an inverted channel l1 and toprovide for bending tubes at three points, one end of said channelprojects at an angle to the main body thereof, as indicated at l8. Ofcourse, it will be apparent that where only two bends are required thesemay be made within the length of the'straight body portion of thechannel I'l. Said channel has longitudinal slots 19 foradjustably'mounting the bending dies and holding component parts of saiddies in proper position as described below.

A separate bending die 20 is provided for each bend to be made in a tubeso there may be one or more of said bending dies and those at oppositeends of the channel will operate in opposite directions although theconstruction of all of them is similar. In view of their similarity thedescription of one will apply to all of them.

Each bending die includes a plate 21 resting on top of the channel I!and on the underside of the plate are lugs or keys 22 which project intothe channel slot l9 to hold said plate against turning or misalignmentwhile permitting it to slide along the channel within the limits of aslot. The plate 2| also carries a fastening'device 23 to temporarilyclamp the bending die in any adjusted position and said fastening deviceis, preferably, a stud fixed in the underside of the plate andprojecting through the channel slot with a nut and washer to enga e theunderneath face of the channel. In lieu of the stud and nut, a bolt canbe used which is projected through the slot and screwed into the plate.

A die segment 24 is carried by the plate 2|, being mounted in place, inspaced relation to and above said. plate, by a bolt 25 and a lug 26projecting from the top face of said plate. This die segment has a tail2! which is straight and lies parallel with the adjacent edge of theplate 2| and in the rim of said segment and its tail is a semi-circulargroove 28 to receive a portion of the tube being bent.

A bending lever 29 has a long arm 30 projecting into the space betweenthe die segment 24 and the plate 2| and fulcrumed at its extreme innerend on the bolt 25 which is in the axis of the curved rim portion of thedie segment. In addition to the long arm 36, there is a short arm 3|which overlies the outer portion of the long arm in spaced relationthereto. The inner end of'the short arm 3! terminates short of the rimof the die segment 24 leaving a space for the insertion of a tube. Botharms 30 and 3| have L-shaped slots 32 directly in line with each other.body portions of these slots are longitudinal of the arms and the footportions of said slots extend transversely and in a direction oppositeto the path of movement of the bending lever during a bendingoperations. An axle 33 is mounted on the bending lever 29 and projectsthrough both arms 30 and 3|, being slidably mounted in the L-shapedslots 32 in said arms. The axle 33 is held in place by a head 34 and acotter key 35 with washers between them and the respective arms and theupper end of the axle extends a sufficient distance above the short armto be readily grasped by an operator for use as a handle. On the axlebetween the long and short arms is mounted a grooved wheel 36 to engageand run upon a tube being bent as will be later more fully described.

The amount of bend placed in a tube is determined by a stop button 31selectively placed in any one of the series of holes 38 in the plate 2!.The holes 38 are disposed in the arc of a circle adjacent the rim of thedie segment 24. There are more of these stop buttons having differentsized heads. The various sizes of heads makes it possible to regulatethe movement of the bending lever to very small fractions of an inchalthough the holes 38 are evenly spaced apart.

A clam on one 01' both of the die structures mounted on the straightportion of the channel I! includes a base 39 extending from the forwardedge of a plate 2|. This base may be an integral part of the plate or itmay be fixed to the plate in any suitable manner. Said base has itscentral portion'cut out and grooves 46 formed in the inside edges toreceive the laterally projecting ears 4|, Fig. 9, of the clamp jaw 42which has an arcuate groove in its inner face.

The clamp jaw is pushed forward by the eccentric cam 43 having a handle44 and mounted on an axle 45 supported by the threaded bearing rods 46mounted in the upstanding foot 4'! projecting from the outer end of thebase 36. The bearing rods are held in their adjustments by nuts on saidrods engaging opposite faces of the foot 41.

In order to properly position a tube for bending, a'tube stop'isprovided which includes a pair of brackets 48 secured to the front edgeof the channel ll. Extending across the space between said brackets andsecured thereto is a rod 49 and on the latter is slidably mounted a mast56, held in any adjusted position by a set screw The mast carries anapertured boss in which a short reach rod 52 is slidably mounted andsecured in any desired adjustment by a set screw 53. That portion of themast above the reach rod functions as a handle. On the outer end of thereach rod 52 is fixed a stop plate 54 to be engaged by the end of a tube55 prior to being clamped for bending.

In operation, assuming that the clamp jaws 42 are retracted as in Fig.5, the bending levers 29 drawn back and the wheels 36 on said bendinglevers in their outermost positions, then the tube 55 is inserted in themachine by passing it vertically between the inner ends of the shortarms 3| of the bending levers 29 and the rims of the die segments 24which-are located on the The straight portion of the channel ll. Thusthe tube is simultaneously placed in two dies and the clamps. Thehandles 44 of the cams 4-3 now are drawn up which will swing said camsover to move the clamp jaws 42 inward and clamp the tube 55 against thetail 21 of the die segment, as in Fig. 7. Of course it is to beunderstood, that when the tube is first inserted in the machinevertically, it is then moved longitudinally until an end strikes againstthe tube stop plate 54 for locating the bending points. Next, the upperextending ends of the axles 33 are moved inward along the body or shankportions of the L-shaped slots 32 to the foot portions thereof so thatparts of the tube are in the grooves of said wheels 36 and the groovesof the die segments 24 located on the straight portion of th channel IT.The bending levers are then swung in the proper directions towards theadjacent ends of the tube, one clockwise and the other counterclockwise,until their movements are arrested by their respective stop buttons 31which have been previously positioned according to the amount of bend tobe made in the tube. Upon the initial bending movement of the bendinglevers the axles 33 will be forced into the feet of the L-shaped slots32 so as to retain the wheels 36 in proper relation to the die segment.Since the wheels 36 run over the tube and the latter is embraced betweensaid wheels and the die segment, the tube will be bent without deformingthe cross sectional contour thereof.

The above operations complete the making of two bends in the tube butwhere another or other bends are to be made also, the bending lever ofthe die on the oblique portion of the channel H is thrown over to anextreme position as shown in Fig. 1. In this case, the making of theintermediate bend will force the end of the tube into the groove of thetail of die at the left hand side of Fig. 1. By swinging the bendinglever of said left hand die inward, the arms 36 and 3i thereof will bepassed over the end of the tube and the grooved wheel 36 may then bemoved inward and the bending lever swung outward to make a subsequentbend.

Upon completion of the bending operations, the bending levers arereturned to their inoperative positions and the cam handles 44 arethrown back to relieve the clamping pressure from the tube. Thereafterthe tube is pulled back laterally which will slide the clamp jawsoutward permitting the tube to be lifted upward out of the clamps andbetween the inner ends of the short arms of all bending levers and theirrespective die segments. After removal, the tube may be transported toany desired location or temporarily laid upon the bench I6.

This method of bending tubes on an apparatus of the character describedaccomplishes the work at an exceedingly high rate of speed and since itonly requires the manual labor of an unskilled operator the cost is verylow.

Of course I do not wish to be limited to the exact details ofconstruction herein shown and described as these may be varied withinthe scope of the claims without departing from the spirit of myinvention.

Having described my invention what Iclaim as new and useful is:

l. A tube bending machine including an inverted channel having oneoblique end, said channel having a number of longitudinal slots therein,die mechanisms mounted on said channeL means carriedby said mechanismsand registering with the slots to hold said mechanism in any preselectedadjustments within the limits of the respective slots, means carried bysaid mechanisms and also registering with said slots to prevent turningof said mechanisms, each of said mechanisms including a die segmenthaving an arcuate groove in the rim thereof, a bending lever pivotedaxially of the rim of said segment, a grooved wheel axially adjustableon the lever, means to clamp a tube to be bent, brackets on the channeland projecting forwardly, a rod secured in said brackets, a mastslidably mounted on said rod, a reach rod slidably mounted on the mast,a stop plate carried by the outer end of the reach rod, and means totemporarily hold said first mentioned rod and the reach rod in anypreselected adjustment.

2. A tube bending machine including a support member having one obliqueend, said support member having a number of longitudinal slots inendwise spaced relation, die mechanisms mounted on said support member,means carried by said mechanisms and registering with the slots to holdsaid mechanisms in any preselected adjustments within the limits of therespective slots, means carried by said mechanisms and also registeringwith said slots to prevent turning of said mechanisms, each of saidmechanisms including a die segment having an arcuate groove in the rimthereof, abending lever pivoted axially of the rim of said, segment, agrooved wheel mounted on said bending lever and axially adjustablelengthwise and laterally thereof, and means to clamp a'tube to be bent.

3. In a tube bending machine, a support memher having a straight portionand one oblique end, die mechanisms slidably mounted on both thestraight portion and the oblique end of said support member foradjustment to and from one another to position, them at preselectedlocations where a pipe is to be bent, each of said mechanisms includinga die segment and a bending lever and a grooved wheel, and means toclamp a tube in a stationary position while being bent.

4. In a tube bending machine, a support member having longitudinal slotstherein, a plurality of die plates mounted on top of said supportmember, means on said die plates and projecting through the slots tohold said die plates in any adjusted position, die segments havinggrooves in the rims secured to said die plates, bending levers eachincluding a long arm pivoted beneath a segment and a short arm spacedabove the outer portion of said long arm and terminating short of thesegment rim to permit passage of a tube between the inner end of theshort arm and the segment, said arms having L-shaped slots in verticalalignment, with the feet of said slots in the region of the inner end ofthe short arm, an axle in said slots, a grooved wheel on each axle, eachof said die plates having a series of holes disposed about the rim ofthe segment, and a button stop selectively placed in one of said holes.

5. In a tube bending machine, a support member having longitudinal slotstherein, a plurality of die plates mounted on top of said supportmember, means on said plates and projecting through the slots to holdsaid plates in any adjusted position, die segments having grooves in therims secured to said die plates, bending levers each including a longarm pivoted beneath a segment and a short arm spaced above the outerportion of said long arm and terminating short of the segment rim topermit passage of a tube between the inner end of the short arm and thesegment, said arms having L-shaped slots in vertical alignment, with thefeet of saidslots in the region of the inner end of the short arm, anaxle in said slots, and a grooved wheel on each axle, in combinationwith clamping means, each including a base with track grooves in thesides thereof, a foot at the outer end of the base, a clamping jawhaving an arcuate groove for cooperation with a portion of the diesegment and 'slidably mounted in the track grooves of the base, a pairof threaded bearing rods adjustably mounted on the foot, a cam pivotedbetween the bearing rods, and a handle on the cam to operate' thelatter.

ROBERT F. BURKE.

